To assess, from the best evidence available, the effects of interventions such as
tocolysis, acoustic stimulation for midline spine position, regional
analgesia (epidural or spinal), transabdominal amnioinfusion, systemic
opioids and
hypnosis, or the use of abdominal
lubricants, on ECV at term for successful version, presentation at birth, method of birth and perinatal and maternal morbidity and mortality.
SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2014) and the reference lists of identified studies.
SELECTION CRITERIA: Randomised and quasi-randomised trials comparing the above interventions with no intervention or other methods to facilitate ECV at term.
DATA COLLECTION AND ANALYSIS: We assessed eligibility and trial quality. Two review authors independently assessed for inclusion all potential studies identified as a result of the search strategy and independently extracted the data using a specially designed data extraction form.
MAIN RESULTS: We included 28 studies, providing data on 2786 women. We used the random-effects model for pooling data because of clinical heterogeneity between studies. A number of trial reports gave insufficient information to allow clear assessment of risk of bias. We used GradePro software to carry out formal assessments of quality of the evidence for beta stimulants versus placebo and regional
analgesia with
tocolysis versus
tocolysis alone.Tocolytic parenteral beta stimulants were effective in increasing cephalic presentations in labour (average risk ratio (RR) 1.68, 95% confidence interval (CI) 1.14 to 2.48, five studies, 459 women, low-quality evidence) and in reducing the number of
caesarean sections (average RR 0.77, 95% CI 0.67 to 0.88, six studies, 742 women, moderate-quality evidence). Failure to achieve a cephalic vaginal birth was less likely for women receiving a parenteral beta stimulant (average RR 0.75, 95% CI 0.60 to 0.92, four studies, 399 women, moderate-quality evidence). No clear differences in fetal
bradycardias were identified, although this was reported for only one study, which was underpowered for assessing this outcome. Failed
external cephalic version was reported in nine studies (900 women), and women receiving parenteral beta stimulants were less likely to have failure compared with controls (average RR 0.70, 95% CI 0.60 to 0.82, moderate-quality evidence). Perinatal mortality and serious morbidity were not reported. Sensitivity analysis by study quality was consistent with overall findings.For other classes of
tocolytic drugs (
calcium channel blockers and
nitric oxide donors), evidence was insufficient to permit conclusions; outcomes were reported for only one or two studies, which were underpowered to demonstrate differences between treatment and control groups. Little evidence was found regarding adverse effects, although
nitric oxide donors were associated with increased risk of
headache. Data comparing different
tocolytic drugs were insufficient.Regional
analgesia in combination with a
tocolytic was more effective than the
tocolytic alone for increasing successful versions (assessed by the rate of failed ECVs; average RR 0.61, 95% CI 0.43 to 0.86, five studies, 409 women, moderate-quality evidence), and no difference was identified in cephalic presentation in labour (average RR 1.63, 95% CI 0.75 to 3.53, three studies, 279 women, very low-quality evidence),
caesarean sections (average RR 0.74, 95% CI 0.40 to 1.37, three studies, 279 women, very low-quality evidence) nor fetal
bradycardia (average RR 1.48, 95% CI 0.62 to 3.57, two studies, 210 women, low-quality evidence), although studies were underpowered for assessing these outcomes. Studies did not report on failure to achieve a cephalic vaginal birth (breech vaginal deliveries plus
caesarean sections) nor on perinatal mortality or serious infant morbidity.Data were insufficient on the use of regional
analgesia without
tocolysis, vibroacoustic stimulation, amnioinfusion, systemic
opioids and
hypnosis, and on the use of
talcum powder or gel to assist
external cephalic version, to permit conclusions about their effectiveness and safety.
AUTHORS' CONCLUSIONS: Parenteral beta stimulants were effective in facilitating successful ECV, increasing cephalic presentation in labour and reducing the
caesarean section rate, but data on adverse effects were insufficient. Data on
calcium channel blockers and
nitric acid donors were insufficient to provide good evidence.The scope for further research is clear. Possible benefits of
tocolysis in reducing the force required for successful version and possible risks of side effects need to be addressed further. Further trials are needed to compare the effectiveness of routine versus selective use of
tocolysis and the role of regional
analgesia, fetal acoustic stimulation, amnioinfusion and abdominal
lubricants, and the effects of
hypnosis, in facilitating ECV. Although randomised trials of
nitric oxide donors are small, the results are sufficiently negative to discourage further trials. Intervention fidelity for ECV can be enhanced by standardisation of the techniques and processes used for clinical manipulation of the fetus in the abdominal cavity and ought to be the subject of further research.